Method of operating a cupola furnace



Nov. 22, 1932. v. s. DURBIN 1,888,759

METHOD OF OPERATING A GUPOLA FURNACE Filed May 4, 1931 FIGJ."

145N708.- V0 TA w 8. DUPB/N.

(B wd Patented Nov. 22, 1932 v ,4; g Q r VOTAW sjni nmmbr Sir. LOUIS, MISSOURI i METHOD "or OPERATING A c'oromi FURNACE c Application filed Maya, 1931; Serial No. 534,756. v This inventionrelates= to certain newv and tuyeres in'stages beginning with thelower setf useful improvements in the method of oper-, and ending with the upper set, and thereby, ating a cupola furnace describedand claimed in operation, gradually raising the height of in my prior Patent No.. 1,778,524, dated the heatingzone, so that, the requisite heat for i Octber14a193O- t I melting can always be maintained, and the w In said prior patent the cupola furnace is necessary amount of oxygen supplied by the: provided with two sets of tuyres at its'lower air blast. I i end, located at different heights, and the The operation, and the advantages thereof,"

nlethodconsists broadly, in first runnin one may be more clearly understood fromithedeheat with the upper set oftuyeres close and tail description to follow.

then, without removing the remaining slag, In the accompanying drawing,which illusa running additional heatswith thelower "set tr'ates the arrangement of the tuyeres of a of tuyeresclosed and the upper set of tuyeres cupola' furnace which'I employ in practicing, open; 1 mymethod p This method of operating'a cupola furnace Figure lis a view inelevation of the-lower 5. haslbeen in actual use'for approximately two part of a c-upolafurnace provided vwith four I years, and is still in'use, andit presents-all of sets of tuyeres arranged accordingto my ini the advantages, outlined in the specification vention; and i a o' [1 V of said patent, as compared with the conven f .FigureQ is a sectional view through one of tional method of runningasin'gle heat and the tuyres, taken on the line 22 of Fig; thereafter dropping the bottom ofithe' furure 1. v q nace to remove the slag. V Figure 3 is a View inbroken'elevation show- It was discovered, however,that after the in aa modified arrangement of the tuyeres; 3 second heat and at the beginning of the'third lteferring now to the drawing, thenumeral heat, it was often impossible to force air .1, indicates thebody of the furnacelwhich, 75

through the upper set of tuyeres in quantity near the bottom, is provided, as usual, with a sufficient to supply the requisite amount of circular ,drum 2. In thepresent instance, oxygen. This was due to th fact that during I drum 2 encloses three sets of superposed, cir-V the preceding heats a certain amount of sla cular series of tuyeres13 formed'in thewall i would collect about the tuyeres and-freeze, of thebody 1, and one of which tuy eres is $9 or harden, with the result'that'the openings shown in Figure: 2. Opposite each ofthe were greatly reduced in size, and the air blast tuyres 3 the wall of drum 2'is provided with correspondingly reduced in capacity. As a" openings 5 opposite,;or inalignment with the. result the molten metal would be relatively opening 3, each opening '5 beingwnormally cold and sluggish. i i closed ya door6, which may be'opened to It has been found,iinpractice, to be 1m permit the operator to open orcloseithe cor practicable,therefore, to runmorethantwlo responding opening 3; These openings are p or three heats without dropping the bottom usually closed by tamping clay into them, of the furnace to remove the accumulated and are" i opened by inserting an iron bar 40 slag This, while representinga decided adthrough each opening 5 and removing the vantage over the prior practice of dropping clay from the-corresponding openings? the bottom after each heat, still did notyield Below the drum 2 the furnace is provided the maximum advantages which,"inprinciple, with the conventional set of tuyeres, each opis capable of being attained by following the posite a duct 7, which are connected to and broad principle of operation set forth in my communicate'ywith the drum 2, through the 90 said prior patent; r a i bottomthereof, by means of air pipes 8,;and

According to the present invention, I over-f theair blast is applied to the drum 2 bymeans come the disadvantage alludedto'by pi'ovid of a pipe 9, leading from the blower, as usual. ing a number of sets of-tuyeresarranged in Asindicated,I preferablyemploy four sets superposed relation, and operating ,thes'e oftuyeres, and for convenience in following 00 .7 the letter B! C, D ,p v H ment is illustrated in Figure"3 ,i'where"the corresponding sets of tuyeres areindicated In operation, the furnacebeing charged,

the three sets of tuyeresB, C andD closed, and 'the set of tuyeres Aiopened, the bedof fuel at the bottomofthe furnace'is ignited are first closed andthe tuyeres B opened, and-- the furnace havingbeen fresh-ly charged, the

and'supplied with a"forced-draft passing throughpip'e 9 'into'th'e' drum 2, through" air pipes 9, and then through 'tuyeres A; Thisis the ordinary operation; After the metalfin the furnace has been melted, it is'runf-out of the "furnace through the discharge openingfrom the furnace, indicated by the "numeral 25 10. 'This operation c'oncludes th e' first-heat,

and at its conclusion, the tuyer'e-openings at 7-' areclosed; and if desiredya-considerable time maybe permitted to elapse before run v I 7 receiving the'molten metal for further heat-' ning the second heat.

In running the second heat, the myersh forced draft is applied asbefore, the air now passing through the tuyere's-BE The secondheat and sometimes-the third; can-usually be" 7 completed with the use, of the tuyeres B only,

' i if heats, -may be runin'ithesaine manner,*+that* and after" the molten. metal has been dischargedfrom the furnace,'-the set' of tuyeres C are opened by removing'the clay from their holes 3', and the next heat isstar'ted, with the blast passing through the'tuyeres B 'and Cu r The next heat,'andone' or moreisucceeding is, with the blast passing through thetuyeres B and G. If it'is' found, however, that slag from the preceding operation has closed'the tuyeres :B and Cto'an extent to impairthe" efficiency of the blast, the tuyeres D maybe opened and succeeding'heats run with the blast passing through the setsof tuyer'es B,

C, and D,or the sets'of: tuyer'es' (I) and. D,

i should the tuyeres B become completely closed. a 7 It will be understood that itis'only necessary to close the tuyeres A after runningthe;

first heat, as in running the subsequent heats the'molten' metal will-never rise sufficiently high inthe furnace to'run out of the tuy'er'es "It will'fuither be understood that'the opensing of the tuyeres C and Disnot11ec'essari'ly coincident with the 'st'arting'of a heatgas these tu'yeres areon'ly opened, in theordr named;-

closi'nga said? Jtuyeresand: runninganother as to render the admission of a stronger blast to the furnace necessary. v v

From the above description of the operation, it will be seen that,as each set of tuyeres is opened, the zone of heat in the furnace will be correspondingly raised, with the result that the metal-above the freshly opened "set of-ituyeres lwill: be zpreheated, as it were, so

,7 that by thetime the molten metalhas reached ,the bottom-ofthefurnace it will be in a more highlyh-eated' cdndition than the blast-had the only interrupt-ion that may i occur in the;

operationrbeing that involved when thefur- V nace is recharged, although usually the'furmelted;

nace is rcoiitinuouslycharged as the metal'is V V While'myiinvention 'may' utilizedpto vantage in operating cupola furnace; its. highestiadvantages" "are der1vedwhen thecupola" furnace is used 111 melting, metal for? makingmalleabl'e iron castings, and is opera a-ted in conj unetion with an airy furnaceafor ing-direct from the; Cupola, furnace, this arrangement, 1 while the charge delivered to the air furnace {is being highly heated pre-- liminary'. to being runrginto the molds, the

cupola furnace can be recl1arged',-or"'the c'hargingi thereof continued, and fresh metal be run nto the air furnace as ,des1red,:some;

or all of the metal in which latter; has in the ingl blasts f to said: furnace ;at higher points'therein. r 2; Thepimetliod' of operating aacupol a' fur-z nace-which consists in running; a: heat with blast" applied at the lower end of said furnace, then closing. the blast openings, and

- successively.

l in

time during the; running of the heats :apply-i without removing the P remaining slag, run-1* ning additional heats-by applying blasts to a the furnace firs-tin aasingle Zone above said:

closed openings and then," at will" in a .plu"- 7 v rality of zonesflocate'd' atsuccessively? in creasing 'heights in the furnace: y Y

3. The -ieth'od 0f melting metalin acupolafurnace having" a plurality of setsoftuyeres at its lower end located at different; heights, which consist-sin runni-ngthe firstv heat with only the lower set of-tuyeres'open,

then; Without-removing. the remaining slag,

heat with only the second set of tuyeres open, and running additional heats with the two lowest sets of tuyeres in the condition last de scribed, and from time to time opening additional sets of tuyeres, in order, above said second set.

4. The method of melting metal in a cupola furnace having three or more sets of tuyeres at its lower end located at dif ferent heights, which consist in first running a heat with the lowermost set of tuyeres open and all the other tuyeres closed, then, without removing the remaining slag, running another heat with the lower set of tuyeres closed and the set immediately above it open, running additional heats with the two lowest sets of tuyeres in the condition last described, and from time to time opening additional tuyeres above the two'lowest sets of tuyeres.

5. The method of operating a cupola furnace which consists in first running a heat with blast applied through conventional tuyeres in the lower end of the furnace, closing said tuyeres and thereafter, without removing the remaining slag, running additional heats, and during the running of said heats gradually increasing the height ofthe heating zone in the furnace by successively applying blasts thereto at zones of applicazone of application supplementinga preceding blast.

In testimony whereof, I have hereunto set my hand.

. VOTAW S. DURBIN.

lasts'thereto at zones of applica- 

